Republican presidential front-runner Donald Trump is taking aim at Hillary Clinton after the Democratic front-runner referred to the real estate mogul as "sexist." Clinton was responding to a question about Trump's use of a vulgar term ["schlonged"] to describe her 2008 primary loss to Barack Obama.

Trump issued a warning on Twitter, telling Clinton to "be careful as you play the war on women or women being degraded card." He later tweeted, "I have great respect for women" and again warned her to "BE CAREFUL!"

Clinton and her team don't seem too concerned about Trump's warnings, reports CBS News correspondent Julianna Goldman. Unlike Trump's Republican rivals who have struggled to confront him, Clinton is playing offense and urging their supporters to step up and express their displeasure with the real estate mogul's choice of language.

"I don't know that he has any boundaries at all," Clinton said in an interview with the Des Moines Register Tuesday.

Clinton said Trump should be held accountable for his language.

"I think he has to answer for what he says ... it's not the first time he's demonstrated a penchant for sexism. And so, I'm not sure, again, anybody's surprised," she said.

Trump fired back Wednesday night.

"I really haven't gone after Hillary yet and there's a lot to go after," Trump said

And so did his political director, Michael Glassner.

"I think it's ironic that Hillary Clinton is playing the sexism card considering the record of her husband and his term in the White House. He was impeached by the House of Representatives for his behavior," Glassner said on CNN.

This whole thing ostensibly blew up because Trump does not like Fox News’ brightest star Megyn Kelly and wanted her removed as one of the moderators of the debate. It was made abundantly clear that if Fox kept Kelly on the panel there would be consequences:

In a call on Saturday with a FOX News executive, [Trump campaign manager Corey] Lewandowski stated that Megyn had a ‘rough couple of days after that last debate’ and he ‘would hate to have her go through that again.’

Trump himself had said something similar, ominously adding,“maybe I know too much about her.” This is patented Trump.

The professional consensus among the Republicans up until now was that this was a mistake because it would turn off women. I'm guessing they feel that ship has sailed. From reading Kellyanne Conway's twitter feed and watching Sean Hannity, it looks more like they think they can push Sanders voting millennials to vote third party giving Trump a plurality. It's really their only hope.

This particular fight is central to Trump's plan. In fact, it is Trump's plan. He knew he was going to be running against a woman and in his juvenile, sexist brain, that's all he needed.